1. Field of the Invention
The present invention relates to an elasticity adjustment structure of physical training device, particularly one that may adjust its elasticity to meet different needs of users.
2. Description of Prior Arts
Principle of conventional martial training device is: one punching bag (such as speed ball or filler bag), when punched by external force, will swing back and forth utilizing elasticity of elastomer connecting to said punching bag.
The elasticity of elastomer of said physical training device is fixed so elastic strength cannot be adjusted for different needs.
Moreover, there is training device utilizing steel tube to change the elasticity of its elastomer. When the punching bag is impacted with external force, the elasticity curve of the said elastomer which it is connected to is not smooth enough. The stress is concentrated on the intersection point of said steel tube and said elastomer; thus, it is easy for the steel tube and elastomer structures to age and be impaired.
Thus, there are foregoing drawbacks of conventional elastic structure of physical training device in prior art to be improved.